In operating a conventional bicycle, a bicycle rider will many times raise himself from the bicycle seat in order to exert a greater downward force on the drive pedals, after which he will relax himself on the bicycle seat. Even though such action is not as necessary with bicycles equipped with gear shifts, a bicycle rider nevertheless will often shift his position on the seat and thus many times raise and lower his body throughout long trips if for no other reason than his comfort.
The foregoing raising and lowering of the bicycle rider's body from the seat represents in certain instances a loss of available energy, particularly when such motion takes place while the bicycle is coasting and the bicycle rider is simply making himself more comfortable. It would be an advantage if such wasted energy could be utilized in aiding the forward propelling force applied to the bicycle.